Shaft and housing connection



March 29, 1966 E. G. F. SWEET 3,242,692

SHAFT AND HOUSING CONNECTION Filed Feb. 24, 1964 FIG.3 FIG.4

INVENTOR EDMUND 6. F. SWEET ATTORNEYS United States Patent 3,242,692SHAFT AND HOUSING CONNECTION Edmund G. F. Sweet, Fergus, Ontario,Canada, assignor to Beatty Bros. Limited, Fergus, Gntario, Canada FiledFeb. 24, 1964, Ser. No. 346,912 Claims priority, application Canada,Mar. 23, 1963, 871,576 2 Claims. (Cl. 644) This invention relates to animprovement in the construction of devices having a rotatably mountedprime mover and a driven element connected thereto by means of a driveshaft. More specifically, it relates to the interconnection of the primemover and the driven element through the drive shaft. A common exampleof the type of device to which the'invention relates is a device knownas a sump pump which has the motor at one end and an impeller assemblyat the other end interconnected by means of a rigid tubular housing fora drive shaft.

The example of the sump pump is a very well known one and the problem ofaligning the journal from which the motor power is taken with thejournal that drives the pump impeller has always been a challenge tomanufacturers. The shaft that interconnects the journal in the pump withthe journal in the motor has, by custom, been a rigid one andmisalignment between the bearings within which the journals rotate hasalways been a source of bearing noise, wear and second power loss. Thesame objectionable characteristics are also caused by deviation fromperfectly straight of the rigid interconnecting shaft. It will beapparent that the free end of a rigid deviating shaft will wobble ortrace out a circular locus as it rotates and any attempt to restrain orcontain the deviation in the locus of the free end of the shaft as itrotates in a bearing will cause wear and noise in the restrainingbearing.

This invention overcomes difficulties of the prior art and achieves aninterconnection of the prime mover and driven element in devices such assump pumps with a minimum of noise, wear and second power loss.According to the invention, a flexible, resilient drive shaft asdistinct from a rigid drive shaft is used to interconnect the primemover with the driven element. The principal axis of rotation of thebearing for the motor is misaligned with the principal axis of rotationof the bearing for the impeller whereby the principal axis of rotationof the journal associated with the motor is misaligned with theprincipal axis of rotation of the journal of the impeller. Themisalignment of the motor and impeller bearings is at least large enoughto flex the resilient drive shaft and maintain the misalignment of thejournals constant as the motor rotates the impeller through the flexibleresilient drive shaft.

The invention will be clearly understood after reference to thefollowing detailed specification read in conjunction with the drawings.

In the drawings:

FIGURE 1 is a side view, partially in section, of a sump pump accordingto the invention.

FIGURE 2 is a view along the line 22 of FIG- URE 1.

FIGURE 3 is a schematic illustration of the interconnection of the sumppump motor and the sump pump impeller and,

FIGURE 4 is a view along the line 44 of FIGURE 3.

The sump pump shown in the drawings has a composite housing comprising amotor housing and a pump housing 12 interconnected by a tubular shafthousing 14 that rigidly connects at one end with the motor housing 10and at the other end with the pump housing 12. The general constructionof the motor, the pump and the housing is well known and not referred toin detail in Patented Mar. 29, 1966 this specification. Numeral 15refers to a standard float switch control for the motor.

The motor rotor is the prime mover of the unit and it is rotatablymounted within the motor housing 10 in a bearing 16 in known fashion.The journal 18, in this case the power take-off from the motor, rotateswithin the bearing 16 and its free end is rigidly connected to the freeend of a flexible, resilient shaft 20 by means of the rigid coupling 22that has set screws 24 and 26 that threadedly engage in the body thereofand exert a clamping force on the journalled free end of the shaft 18and on the free end of the drive shaft 20 respectively.

In this specification, the principal axis of rotation of the bearing 16is concentric with the bearing surface thereof and the principal axis ofthe journal is the central longitudinal axis thereof. Because oftolerance between the bearing and journal, the principal axis of thejournal may not be coincident with the principal axis of the bearing.

Shaft 20 has a journal 28 sweat-soldered to its other end and journal28, is, in turn, mounted for rotation in the bearing 30. Bearing 30 iscarried by the housing 12 of the pump assembly as indicated. Here again,the principal axis of the bearing 30 is concentric with the surfacethereof and the principal axis of the journal 28 is the centrallongitudinal axis thereof and the two axes are not coincident because oftolerances. The pump impeller 29 is carried by the journal 28.

According to the invention, the principal axis of the bearing 16 for thejournal 18 is misaligned with respect to the principal axis of thebearing 30' for the journal 28 whereby, of course, the principal axis ofrotation of journal 18 is misaligned with respect to the principal axisof rotation of the journal 28. In FIGURES 3 and 4 of the drawings, whichare views taken at right angles to each other, the misalignment isrepresented by the letter x in FIGURE 3. This view is taken in a planein which the misalignment is a maximum so that the misalignment in theplane at right angles thereto illustrate in FIGURE 4 is zero.

The shaft 20 is flexed to accommodate the misalignment of the journalsand the resilience of the shaft, which tends to cause it to assume anormal position, constantly urges the journal 28 in the direction of thearrow 32 in FIGURE 3. The misalignment of the bearings is great enoughthat the shaft 20 is fixed during its full rotation of 360 so that theflexibility of the shaft always exerts a force in the direction of thearrow 32 as shown in FIGURE 3. The misalignment of the journals then isalways a constant and equal to the dimension x viewed in FIGURE 3. Theflexibility and resilience of the shaft 20 thus tend to cause thejournal 28 to assume a constant position within its bearing 30 with theresult that noise and wear is reduced to a minimum. A drive shaft in astandard sump pump has a diameter of about /2". This is a rigid shaft.By reducing the diameter to A", it becomes flexible. The reductionactually reduces the rigidity of the shaft by 16 times and theeccentricity described above can be incorporated with no increase inpump bearing load. The necessary eccentricity for the invention is lessthan 16 times the probable misalignment of the free end of the rigidshaft in the pump bearing with the standard design.

The shaft 20 being designed for flexibility is less in weight and inmaterial cost. The invention, therefore, in addition to providing themore quiet operation reduces manufacturing costs. The rigid coupling 22used with the invention is also a relatively cheap component because arigid shaft as used in accordance with the practice of the prior artrequires a flexible and more expensive coupling to be used in place ofthe coupling 22. It will also be apparent that tolerances in thecomponents can be relaxed because the amount of misalignment necessaryto make this invention Work is not as critical as the alignment that wasnecessary in connection With the bearings of the prior art wherein rigidshaft was used.

Embodiments of the invention other than the one illustrated will beapparent to those skilled in the art and it is not .intended that thisinvention should be limited to the embodiment described herein.

What I claim as my invention i825 1. In a device for transmitting powerfrom a rotary prime mover to a driven element, said prime mover having afirst journal extending therefrom, a housing enclosing said prime mover,a tubular shaft housing having aligned openings at each end, bearingmeans mounted in each opening, one of said bearing means being connectedto said housing and the other of said bearing means being connected tosaid shaft housing, said first journal rotating in said first bearing, asecond journal rotating in said second bearing, a coupling secured tosaid first journal, the axis of said one of said bearing means, saidfirst journal and said coupling being concentric to the axis of saidshaft housing, the axis of said other of said bearing means and saidsecond journal being eccentric to the axis of said shaft housing, aresilient shaft having one end secured in said coupling and the otherend secured in said seoond journal whereby said shaft is flexed andmaintained in a stressed condition. I

2. In a device of the class specified in claim 1 in which said shaft isrigidly connected to said first journal.

References Cited by the Examiner UNITED STATES PATENTS 1,145,967 7/1915Bernhard et a1 308-62 1,260,080 3/1918 Singer 642 3,037,573 6/1962Larsen 641 X 3,155,187 11/1964 De Loren 64l X BROUGHT ON G. DURHAM,Primary Examiner.

H. C. COE, Assistant Examiner.

1. IN A DEVICE FOR TRANSMITTING POWER FROM A ROTARY PRIME MOVER TO ADRIVEN ELEMENT, SAID PRIME MOVER HAVING A FIRST JOURNAL EXTENDINGTHEREFROM, A HOUSING ENCLOSING SAID PRIME MOVER, A TUBULAR SHAFT HOUSINGHAVING ALIGNED OPENINGS AT EACH END, BEARING MEANS MOUNTED IN EACHOPENING, ONE OF SAID BEARING MEANS BEING CONNECTED TO SAID HOUSING ANDTHE OTHER OF SAID BEARING MEANS BEING CONNECTED TO SAID SHAFT HOUSING,SAID FIRST JOURNAL ROTATING IN SAID FIRST BEARING, A SECOND JOURNALROTATING IN SAID SECOND BEARING, A COUPLING SECURED TO SAID FIRSTJOURNAL, THE AXIS OF SAID ONE OF SAID BEARING MEANS, SAID FIRST JOURNALAND SAID COUPLING BEING CONCENTRIC TO THE AXIS OF SAID SHAFT HOUSING,THE AXIS OF SAID OTHER OF SAID BEARING MEANS AND SAID SECOND JOURNALBEING ECCENTRIC TO THE AXIS OF SAID SHAFT HOUSING, A RESILIENT SHAFTHAVING ONE END SECURED IN SAID COUPLING AND THE OTHER END SECURED INSAID SECOND JOURNAL WHEREBY SAID SHAFT IS FLEXED AND MAINTAINED INSTRESSED CONDITION.